[webui] add release repository button (FATE #315250)
[dist] remove dead code
[dist] escape macros in comments

Macros are evaluated even in comments.
While this instances does not cause any visible errors, it is safer to
properly escape them.
[dist] Explain how sources are retrieved
[dist] Fedora use different user:group for Apache
[dist] test if user and group exist before trying to add
[dist] define rpm group only for SLE 11
[api] create one unified relationship model

move the relationships of [user|group] and [package|project] into
one table
[api] optimize loading maintainers in /status/project
[api] retire {package|project}_group_role_relationship

prj.project_group_role_relationships is now prj.relationships.groups
(unless you look for a specific group then you it's just relationships)
[api] retire package_user_role_relationship model

self.relationships.users will do for packages, self.relationships.packages will do
for users
[api] retire project_user_role_relationships

self.relationships.users will do for projects, self.relationships.projects
will do for users

also remove the GroupRelationship model I added at some point
[api] avoid too big calls into memcached

Rails.cache.read_multi hangs "forever" with 13000 packages, so divide this
[api] move XML renderer to views where easily possible
[api] remove more of rexml usage
[api] fix testsuite failure
[api] give the group controller a sane structure
[api] fix the testsuite indeed

actually running the tests *does* help ;)
[backend] fix sandbox constraints handling
[webui][api] Introduce comments for projects, package and requests in the API and display them in the UI